Spinneret



1969 R. BRADLEY ET AL 3,478,389

INVENTORS BRucE R. BRADLEY AMES G. sMs

T o N United States Patent oce 3:,478,389 Pafented Nov. 18, 1969 ABSTRACT oE THE DISCLoSURE A Spinnefet aSSembly paTticularly Suitable for Ineltspinning laInentS of noncirculaT cToSS Section is Tovided. The spinnerot iS IIlade of a solid plate having an eXtrusion face and a nlelt face. At least one oTifice eX tends betWeeI1 the faces and iS provided With a countef bore Tnelf Teceiving portion and an extrusion poTtion pTesenting a pluTality of elongated slotS. In the counterboro a Solid discTete sphefoid iS positioned to diveft the How of the n1elt towald the extTemitioS of the elongated slots. TT1is affangeInent Tnakes poSSible a convenient extenSion of the nuInbeI of noncircular cross-sectional Shapes that one can pToduce in filaInentS Inade uSing a given Spinnefet.

BACKGoUND oF THE INvENTION Recently to alteT the pTopefties theTeof the crosS-Sec tional Shape of man-made filaInentS has been n1odied froIn nofmally found to a vaiety of noncifculaf con gufations. FilaolentS having nonciTcular cfoSS Sections have been IIlelt Spn froIn I1any diffeTently shaped spin neret orifices. IIovvever, the numbeT of dieTent Shapes thaf one can obtain ffoIn a given ofifice iS in1ited by festTictionS in changeS that can be Inade in the Spinning conditions to ovefcoole the tendency of the extrudod strean1 to becon1e round TegaTdlesS of What crosS-Sectional shape the spinneret paSSage Inay have iInpafted. The actual Shape of the IaInent Shape TesoolbleS the cToss Section of the Spinnefet ofifice fTom vVhich the fila Inent extTudeS to a greatof of lessef degTee, depending upon the specific spinning Conditions. It iS vvell fecognized, fof exalTlple, that the nSe of veTy high viScoSity olynler and very Ta id nenchin of the extruding iila- InentS favofs fetention of tho noncifcular Shape siIT1ilaf to the oriffce. Fof a given siZe and shape of SpinneTet oTifice, however, only a felatively naffovv Ta nge of spinning conditions are opeTable practicaHy; hence, When the deSired filan1ent cfoSS-Sectional Shape is not achieved, the only pTactical sollltion hefetofoTe haS been to nlake a nevv SpinneTet having diffefent diInensionS that Wi11 yield the Tequifed fflanlent Shape. The obvious dfaWback to thiS is that noncifcular capillaries have been and contioue to be diicult to Inake and aTe qoite ex ensive. In accordance vvith the pTeSent invention, a very siInple pTocedUre of extending the range of mament ShapeS possible With a given S inneret undeT )Tactical operating conditions iS pTovided.

111 the pfior art it has been pfopoSed t.11at the Inofe open ceI1tTal aTea of the ofince be blocked by insofting a cofe of pin i11 the oTifice. In pTactice such co1 es InUSt be veTy accnTately nlachined and oxacfly centefed of the polymef ow iS Severely diStofted, cauSing nlalformed mamentS, Such pinS have been of no known pTactica 11tility even in hoHovv iilaInent SpinI1ing and aTo too expensive fof genefal l1Se.

TheTefore, it is an obiect of the pfesent invention to provide a spinneTet adapted fo1 spinning filanlents having a large1 Tange of non-ciTcular cfoSS sectiooS than one can norInally obtain fof a given oIifice design.

SUMMARY oF THE INVENTION A Spinneret for nlaking laInentS of ooncirculaf cToSS Section is provided and compTiSeS a solid plate having a spinning Uid delivery face and an extfusion face. z^ft 1east one orce eXtendS betWeeo the faces to pfovide a passagevay fo1 extrusion of the uid into filaInents. The olifice haS a poTtion of laIgef cIOSS-Sectional afea ad acent the eXtfuSion face and a poftion of SInallef cToSs Sectional afea adjaceot the deliveTy fa'ce. The boonding vva11 denning fhe ofifice encloSeS a plufality of elongated Slots at the eXtTusion face. Dotachably poSitioned in the portion of laTgef aTea iS a SpheToid fof divefting the ovv of the Spinning fluid toWaTd the extren1ities of the e1on gated SlotS. ThiS pTovides a si1Tlple expedient for oxtending the opeTable Tange of a noncircular SpinneTet oIioce.

DESCRIPTTON oF THE DRAWING T he invention can best be underStood by TefeTence to tho fonovving description taken in coniunction vvith the accompanying dfaWing in Which= FIGURES 1 and Z aTe scheInatic lateTal Section views throngh a Single spinnefet orifice of capillaTy, including the counteTbofe, a spheTical ba11 being ShowI1 in the Countefbore UpstreaIn of the noncifcUlar capHlary poT tion; and

FIGURES 3 4 and 5 innstrate s inneTet ofinces and typical but enlaTged cfosS SectionS of filan1entS Spun through these oTifices; Z) gufeS aro illUStrative of the filanlent sectionS Spun directly ffon1 the SpinneTet oTificeS, o without the polyIIler diveTting ba11 and the c' gUTeS aTe illllstTative of the filaInent sectionS Spun with a spheTi caJl ball in the counterboTeo vVith refeTence to FIGURE 1, there is shovvn a se ment of a Spinneret 1 usuany Inade of a solid Inetal plate of thickneSS Suitable to withStand noTmal eXtfUsion pfes- SUTes, The spinneTet iS adapted for inclusion in a Standard spinning block aSSeTnbly and haS at leaSt one spinning ofifice and in Some instanceS Sevofal hundTed orificos. Fof SiIT1 )1icity of illustration, the views in FIGURES 1 and 2 each Shovv only one oTifice Z. The SpinneTet haS a Spinning uid dolivery face 3. TTle nid io melt Spinni11g operationS is IT1olteI1 polyIner Which SeekS the eXt pTo vded by the oTinces. The arTows 4 indicate the oW path of Spinnig uid thfough the o1 iiice to the diSchaTge side of the spinneTet having eXtrnsion faco 5. ofince 2 dened by a bounding vva11 has an upper counteTbore por tion o of laTger crossSectional aTea and has a capillaTy poftion 7 of Sn1allef cToss-Sectional aTea. The bounding vvan at the extruSion face encloses a plI1rality of e1on gated slots best Seon in FIGURES 3o, 4o and So. An unannexed spheroid taking the pTeferfed fofII1 of a lT1etal ball -8 is inSerted in the countefboTe poftion.

Meta1 sphefical baHS aTe pTofeTred because of Teady availability, and the highof theTmal conductivify of tlle II1eta1 helps to equaliZe the teITlpeTatuTo of Inolten poly Inef enteTing the capillary. Ban beaTingS of variouS alloyS incloding co1T1Inon Stainless steelS, S11ch as type 316, caI1 be oSed and ae manufactofed to extTemely close dimen Sional tolefances.

The bottom of the counteTbore for noncifculaf ofifices iS pTefefably nlade at iI1 ofder to have a TepToducible conStant capfllaTy length aS illHStfated in FIGURE 1. However, most tWist dTinS have at least a slight conical point to centef the dfiH a counteTbore dTined with Such Standard dTill iS illI1StTated in FIG. Z, and is altogethef SatisfactoTy When a ba11 iS placed as shoWn i11 the conntef bofe; Without the balL polyIner channelS SeveToly into the cente1 of this countefbofe vvhich iS II111ch inferiof to the 1iat-bottoIned connteTbofe.

It haS been found that the spherical ban is Selfcentering in the polymer stfean1 so that the baHS can be n1efely 

